Ory Kratos vs ZITADEL
A side-by-side comparison of two self-hosted identity & sso options — licensing, setup difficulty, resource needs, and what each one replaces.
ZITADEL
Cloud-native identity infrastructure with multi-tenancy built
| Feature | Ory Kratos | ZITADEL |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 89 · Excellent | 95 · Excellent |
| Category | Identity & SSO | Identity & SSO |
| License | Apache-2.0 | Apache-2.0 |
| Language | Go | Go |
| Setup difficulty | Hard | Medium |
| Min. RAM | 256 MB | 512 MB |
| Deployment | docker, kubernetes, binary | docker, kubernetes, binary |
| GitHub stars | ★ 13,888 | ★ 15,083 |
| First released | 2020 | 2020 |
| Replaces | Auth0, Firebase Auth | Auth0, Okta, Firebase Auth |
What are Ory Kratos and ZITADEL?
Ory Kratos
Ory Kratos is an API-first identity and user management system. It handles login, registration, profile management, account recovery and multi-factor authentication without prescribing a user interface.
- Headless API for full UI control
- Self-service flows for login and recovery
- Pluggable MFA including TOTP and WebAuthn
- Cloud-native and stateless design
ZITADEL
ZITADEL is an open-source identity and access management platform built for multi-tenant applications. It offers OpenID Connect, OAuth2, SAML, passwordless login and a powerful management API.
- Multi-tenancy as a first-class concept
- Passwordless and FIDO2 authentication
- Event-sourced audit trail
- Comprehensive gRPC and REST APIs
Ory Kratos vs ZITADEL: key differences
Both projects are written in Go. Ory Kratos is the lighter option, starting around 256 MB of RAM against 512 MB for ZITADEL.
Why pick each one
Choose Ory Kratos if…
- Extremely flexible architecture
- Excellent for custom frontends
Watch out for
- Requires building your own UI
- Complex initial setup
Choose ZITADEL if…
- Strong multi-tenant model
- Modern Go codebase
Watch out for
- Smaller community than Keycloak
Frequently asked questions
Is Ory Kratos or ZITADEL better?
ZITADEL is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider Ory Kratos if its specific feature set fits your needs better.
Are Ory Kratos and ZITADEL free and open-source?
Yes. Ory Kratos is licensed under Apache-2.0 and ZITADEL under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Ory Kratos and ZITADEL with Docker?
Ory Kratos: yes. ZITADEL: yes.
Which is lighter on resources, Ory Kratos or ZITADEL?
Ory Kratos has the smaller minimum footprint at 256 MB of RAM, compared to about 512 MB for ZITADEL. Real-world usage depends on library size, user count, and enabled features.